The stimulation of the cochlea performed by a cochlear implant typically includes the reception of sound by a microphone placed near to a patient's ear and based on the analysis of this sound, the choice of a set of electrical injection contact points to be stimulated along the cochlea, the current levels to be injected at the injection electrical contact points and for each injection contact point a set of current return points and the current levels to be accepted at each one of these points, or alternatively, an opposite polarity voltage level to be placed at each current return contact point. A problem that has been encountered in cochlear stimulation is that of a fairly small dynamic range of stimulation. That is, the loudest sound comfortable to a patient (the “maximum comfort level” or MCL), is not as much greater than the softest sound detectable by the patient (the “threshold intensity”) as is the difference between softest sound and loudest sound in a natural hearing person.
U.S. Pat. No. 6,480,820, which is incorporated by reference as if fully set forth herein, discloses a method for recognizing sound events that may then form the basis for a scheme of cochlear stimulation. First a vector comprised of the instantaneous phase and magnitude of a sound signal time sample from one band pass filter, is computed. Then the moments when this vector passes the real axis are determined and the magnitude of the vector at these moments is determined. In the following text, these values are described as mt, the desired strength of stimulation. Other methods, however, may be used to find a set of values, mt.